Doonium

"Doonium has been the metal alloy of choice for nearly 10 centuries in capital starship construction. The distinctive white-gray cast of the battlecraft constructed with doonium has become synonymous with serious naval power."
―Harod Crimmler of the Historical Battleship Preservation Association, as quoted in Imperial Defense Daily

Doonium was a heavy metal primarily used in starship hull construction. It gave ships such as those in the Imperial Navy their characteristic white-gray color. Doonium was mined primarily from asteroids and other small planetoids. The Empire granted exclusive mining contracts to companies like Turlin Corp to provide the needed ore.

Between the Battle of Yavin and the Battle of Hoth, the Galactic Empire experienced a raw materials shortage that included a shortage of doonium. As a result, many ships languished in spacedock without proper hull plating. To clear space in the Kuat drydocks, a flotilla of Victory-class Star Destroyers was equipped with red havod alloy hulls instead of the traditional doonium.

One source for the metal was the mines of the Thrugii Asteroid Belt in the Socorro system. Other sources included Dor and Atraken.